Field of the Invention
The present invention relates to a bead member manufacturing method for manufacturing a bead member by forming an annular bead filler in an outer peripheral side of an annular bead core.
Description of the Related Art
An annular bead core is provided in a bead portion of a pneumatic tire, and a bead filler is provided in an outer side in a tire diametrical direction of the bead core. As a method of forming a pneumatic tire, there is a method of previously manufacturing a bead member by integrating a bead core and a bead filler and forming the pneumatic tire by combining the bead member with the other tire component members.
The bead member is manufactured, as shown in FIG. 9, by forming a bead filler 200 by winding a rubber discharged from a mouth piece of an extruder around an outer peripheral side of a bead core 100 which is fixed to a forming surface 300 of a forming table. At this time, for example, in the case that a cross sectional shape of the bead core 100 is a hexagonal shape as shown in FIG. 9, the rubber is hard to enter into a narrow space between a side surface 100a in a width direction of the bead core 100 and the forming surface 300, and a gap tends to be generated between the side surface 100a in the width direction of the bead core 100 and the bead filler 200. As a result, a problem such as air intrusion and adhesion failure between the bead core and the bead filler is caused when the pneumatic tire is formed.
In the following patent document 1, there is described a tire manufacturing method for forming a bead portion by combining a bead core and a bead filler, the method including a step of forming a first bead filler area only in a portion coming into contact with the bead core among an area in an inner side in a width direction of the bead core by winding a ribbon-like bead filler rubber, a step of assembling the bead core in an outer side in a width direction of the first bead filler area by moving the bead core from an outer side in the width direction toward an inner side in the width direction in relation to the formed first bead filler area, and a step of forming the remaining bead filler area by winding the ribbon-like bead filler rubber.
Further, in the following patent document 2, there is described a forming method of a bead core assembly obtained by integrating an annular bead core and an annular bead filler, the bead filler including a first rubber body and a second rubber body, and the method including a first forming step of forming the annular first rubber body by winding a ribbon-like rubber material on a support member, a second forming step of forming the annular second rubber body by winding the ribbon-like rubber material on the bead core, and an integrating step of integrating the bead core and the second rubber body with the first rubber body on the support member after the first forming step.
According to the patent documents 1 and 2, since the bead core is assembled on the previously formed first bead filler area or the first rubber body, it is possible to theoretically do away with a gap between the side surface in the width direction of the bead core and the bead filler. However, it is hard to accurately arrange the bead core along the shape of the first bead filler area or the first rubber body, and there is a risk that any gap is generated between the side surface in the width direction of the bead core and the bead filler.